Door closer

ABSTRACT

A door closer comprises a housing defines an interior cavity. A spindle is journaled in the housing. At least a portion of the spindle extends from the housing and is connected to turn with a door. A cam is carried by the spindle for rotation with the spindle. A slide assembly includes a cam following roller for cooperating with the cam for converting rotation of the cam into linear movement of the slide assembly relative to the housing. A piston is disposed in a cylindrical recess and a piston rod connects the piston and the slide assembly. Spring means disposed outside of the housing urge the piston and slide assembly in the door closing direction. The spring means includes a spring rod connected to the piston. Passage means defined in the housing permit flow of fluid between the cylindrical recess and the cavity in a closed end of the housing in response to movement of the piston. Upon rotation of the spindle and cam in the door opening direction, the cam operates against the cam following roller for moving the slide assembly thereby compressing the spring means for storing energy. The spring means urges the piston and the slide assembly in the opposite direction, and the cam following roller against the cam to rotate the cam and the spindle in the door closing direction.

BACKGROUND OF INVENTION

This invention relates generally to a door closer, and more particularlyto a door closer for automatically moving a door from an open positionto a closed position.

A conventional automatic door closer operates by storing energy in aspring mechanism during opening of a door and releasing the storedenergy to close the door. Automatic door closers are provided with meansfor controlling the movement of the door, usually involving hydraulicresistance within the door closer. When the door approaches a fully openor the closed position, a fluid medium within the door closer is causedto flow through restrictive passages which determine the speed of doormovement.

A typical automatic door closer generally comprises an elongated housingwhich may be mounted above the door, in the transom or lintel, or in thefloor. A rotating spindle is disposed adjacent one end of the housingsuch that an end of the spindle extends from the housing for connectingto the door. The portion of the spindle within the housing is connectedfor rotation with a cam mechanism. During movement of the door from theclosed position to an open position, the cam mechanism acts against atleast one adjacent roller fixed to a slide assembly for moving the slideassembly longitudinally in the housing. The slide assembly is connectedto a piston in a hydraulic dampening arrangement. The piston divides atleast a portion of the interior of the housing into two pressure spaceswhich are connected to each other by one or more passages for therestricted flow of the fluid medium from one space to the other.

In operation, the spindle and the cam mechanism rotate with the door.When the door moves from the closed position to an open position, thecam mechanism abuts against the roller and moves the slide assembly andthe piston from a first position towards one end of the housing. Thiscompresses the spring mechanism and the piston forces fluid to flow fromone pressure space to the other. The spring mechanism also provides someresistance to the opening of the door to prevent the door from suddenmovement. When the door is released, the stored energy of the compressedspring mechanism supplies energy for closing the door. As the door movesback to the closed position, the extending spring mechanism urges thepiston and slide assembly to return to the first position causing theroller to act against the cam for rotating the cam mechanism and spindleand moving the door to the closed position. The speed of closingmovement is controlled by the passage of fluid from one pressure spaceto the other caused by the piston.

A problem with door closers of this type includes the immersion of theoperative elements of the door closer in hydraulic fluid. The necessaryuse of fluid seals and other components lend themselves to possibleleakage, which constitutes a safety hazard and can have a damagingeffect on the door and floor below.

For the foregoing reasons, there is a need for an automatic door closerwhich minimizes the number of door closer elements immersed in fluidmedium and thereby reduces the problem of preventing possible leakage.

SUMMARY OF INVENTION

According to the present invention, a door closer is provided forautomatically moving a door in a closing direction. The door closercomprises an elongated housing having a first closed end and an opensecond end and defining an interior cavity including a cylindricalrecess spaced from the first end of the housing. A spindle is journaledin the housing adjacent the first end of the housing for rotation aboutan axis. At least a portion of the spindle extends from the housing andis adapted to be connected to turn with the door. A cam is carried bythe spindle for rotation with the spindle about the axis through an arcin a first direction from a first angular orientation corresponding tothe closed position of the door to a second angular orientationcorresponding to an open position of the door and about the axis throughan arc in an opposite direction from the second angular orientation tothe first angular orientation. Rotation of the cam from the firstangular orientation to the second angular orientation corresponds tomovement of the door in the opening direction and rotation of the camfrom the second angular orientation to the first angular orientationcorresponds to movement of the door in the closing direction. A slideassembly includes a cam following roller for cooperating with the camfor converting rotation of the cam into linear movement of the slideassembly relative to the housing. A piston is slidably disposed in thecylindrical recess and a piston rod is connected at one end to thepiston and at the other end to the slide assembly. Spring means disposedoutside of the housing urge the piston and slide assembly in the doorclosing direction. The spring means includes a spring rod connected atone end to the second end of the piston. First and second annular plugsare disposed in the housing adjacent the ends of the cylindrical recessfor slidably sealingly receiving the piston rod and the spring rod,respectively. The first and second annular plugs and piston divide thecylindrical recess into a first chamber between the first annular plugand the end of the piston and a second chamber between the secondannular plug and the other end of the piston. Passage means defined inthe housing permit flow of fluid between the cylindrical recess and thecavity between the first annular plug and the closed end of the housingin response to movement of the piston. Upon rotation of the spindle andcam in the door opening direction, the cam operates against the camfollowing roller for moving the slide assembly toward the first closedend of the housing and the piston toward the first end of thecylindrical recess thereby compressing the spring means for storingenergy. The spring means urges the piston toward the second end of thecylindrical recess for moving the slide assembly toward the second endof the housing and the cam following roller against the cam to rotatethe cam and the spindle in the door closing direction.

BRIEF DESCRIPTION OF DRAWINGS

For a more complete understanding of the present invention, referenceshould now be had to the embodiments shown in the accompanying drawingsand described below. In the drawings:

FIG. 1 is a side elevation view of an embodiment of a door closeraccording to the present invention showing a longitudinal cross sectionof the housing, damping portion and spring assembly.

FIG. 2 is a bottom plan view of the door closer as shown in FIG. 1.

FIG. 3 is a bottom plan view of the door closer as shown in FIG. 2 withthe spindle cap removed and showing a longitudinal cross section of aportion of the damping portion of the housing.

FIG. 4 is a top plan view of the door closer shown in FIG. 1.

FIG. 5 is a side elevation view of the damping portion of the doorcloser shown in FIG. 1 with an internal cylinder and fluid passagesshown in phantom.

DETAILED DESCRIPTION

Certain terminology is used herein for convenience only and is not to betaken as a limitation on the invention. For example, words such as“upper,” “lower,” “left,” “right,” “horizontal,” “vertical,” “upward,”and “downward” merely describe the configuration shown in the FIGs.Indeed, the components of the door closer may be oriented in anydirection and the terminology, therefore, should be understood asencompassing such variations unless specified otherwise.

As used herein, the term “open position” for a door means a doorposition other than a closed position, including any position betweenthe closed position and a fully open position as limited only bystructure around the door frame, which can be up to 180° from the closedposition.

Referring now to the drawings, wherein like reference numerals designatecorresponding or similar elements throughout the several views, a doorcloser according to the present invention is shown in FIGS. 1-4 andgenerally designated at 10. The door closer 10 comprises a housing 12and a spring assembly 18. The housing includes a mechanical end portion14 and a dampening end portion 16.

The mechanical end portion 14 defines an interior cavity 15 and hasopenings into the cavity 15 in a major face and at one end of themechanical end portion 14. The cavity 15 in the mechanical end portion14 accommodates a spindle 20, a cam assembly 22, and a slide assembly24. The spindle 20 is rotatably mounted in the cavity 15 and extendsnormal to the longitudinal axis of the housing 12. An inner cylindricalend of the shaft of the spindle 20 is supported in an annular bore inthe housing 12 by an inner roller bearing 26. The opening in the majorsurface of the mechanical end portion 14 is internally threaded forreceiving an externally threaded spindle cap 28. The spindle 20 has anintermediate cylindrical shaft portion journaled in an outer rollerbearing 30 held within a rim in the spindle cap 28 for rotatablysupporting the spindle 20. The outer end of the shaft of the spindle 20extends through an opening in the spindle cap 28 outwardly of thehousing 12. The spindle 20 and spindle cap 28 are sealed by o-rings 32,34 which prevent leakage of a hydraulic working fluid from the interiorcavity 15 of the housing 12.

The cam assembly 22 comprises an eccentric cam 36. The cam 36 includes afirst cam plate 38 and a second cam plate 40 mounted together in fixedspaced relation to the spindle 20 for rotation with the spindle 20. Eachof the cam plates 38, 40 has a peripheral camming surface. As best seenin FIG. 3, the cam 36 is a double-acting butterfly type cam, which issymmetrical about its centerline.

Referring to FIG. 1, the slide assembly 26 comprises upper and lowerdraw bar plates 42, a draw bar rod 44, and a cam follower 43. The drawbar plates 42 are connected to each other in spaced parallel relationabove and below the cam 36 by a pair of vertical trunions 46 (FIG. 3),the ends of which are located in corresponding bores in the draw barplates 42. Each of the trunions 46 mounts rollers 50 (FIG. 1) betweenthe draw bar plates 42. The rollers 50 are positioned diametricallyopposite each other with reference to the axis of rotation of thespindle 20. The rollers 50 act as a cam followers which engage and trackthe peripheral surface of the cam 36 during rotation of the spindle 20and cam 36. The draw bar plates 42 have opposed elongated guide slots 48(FIG. 3) through which the spindle 20 extends. As will be described morefully below, the slide assembly 24 is reciprocal in the housing 12 inresponse to rotation of the spindle 20 and cam 36 and is guided forlongitudinal movement by the spindle 20 moving in the slots 48 in thedraw bar plates 42.

As seen in FIG. 3, the draw bar rod 44 is T-shaped. The head portion ofthe “T” has openings at each end for receiving threaded fasteners 52 forsecuring the draw bar rod 44 to the end of the draw bar plates 42opposite the cam 36. The distal end of the draw bar rod 44 extends intothe dampening end portion 16 of the housing 12.

The dampening end portion 16 of the housing 12 is secured to themechanical end portion 14 using threaded fasteners received in axialthreaded openings in the corners of the dampening end portion 16 (FIG.3). The dampening end portion 16 of the housing 12 defines an interioraxial cylinder 17 which is open at both ends. An annular back check disc54 is sealingly secured in the end of the cylinder 17 adjacent themechanical end portion 14 of the housing 12. The back check disc 54 isfixed with respect to the cylinder 17 and is sealed to the walls of thedampening end portion 16 with an o-ring 55 disposed in a circumferentialgroove. The back check disc 54 thus effectively separates the portion ofthe cavity 15 in the mechanical end portion 14 of the housing 12 fromthe cylinder 17 in the dampening end portion 16. The back check disc 54slidingly receives the draw bar rod 44 which extends into the cylinder17. The back check disc 54 includes a plurality of ball check valves 56which allow one-way fluid flow from the cavity 15 in the mechanical endportion 14 into the cylinder 17.

A hollow spool-shaped piston 60 is slidably disposed within the cylinder17 for reciprocal movement relative to the housing 12. The annular endsof the piston 60 seal against the wall of the dampening end portion 16defining the cylinder 17 to establish a fluid tight relation between theends of the piston 60 and the housing 12. One end of the piston 60 isconnected to the draw bar rod 44 by means of a pin 62.

A pressure relief valve 64 is disposed in each end of the piston 60.Each pressure relief valve 64 has two axial valves 66, 68. One set ofvalves 66 includes a ball and a spring combination disposed in an innerlarger diameter portion of the one set of passages. The diameter of theballs are larger than a smaller outer diameter portion of the passages.The springs bias the balls against the smaller diameter passage suchthat the passages are normally closed. The other set of valves 68 isone-way ball check valves which prevent the flow of fluid in a directioninto the piston 60. As seen in FIG. 1, there is a slight gap between theinner ends of the pressure relief valves 64. A radial passage in thesmaller diameter middle portion of the piston 60 allows fluid to enterinto the gap and flow out of the ends of the piston 60 through the ballcheck valves 68 of the pressure relief valves 64. Fluid cannot normallyflow into the ends of the piston 60. However, excessive fluid pressureat the ends of the cylinder 17 will cause the balls to unseat allowingfluid to pass to relieve pressure.

An annular check disc 82 is sealingly secured in the distal end of thecylinder 17 of the dampening end portion 16 adjacent the spring assembly18. The check disc 82 is fixed with respect to the cylinder 17 and issealed to the walls of the dampening end portion 16 with an o-ring 84disposed in a circumferential groove on the periphery of the check disc82. The check disc 82 thus effectively seals the distal end of thedampening end portion 16 of the housing 12. As shown in the FIGS. 1 and3, in this arrangement, the piston 60 divides the cylinder 17 in thedampening end portion 16 into a first variable volume chamber betweenone end of the piston 60 and the back check disc 54 and a secondvariable volume chamber between the other end of the piston 60 and thecheck disc 82.

The spring assembly 18 comprises a spring rod 80 and coil compressionsprings 88 supported between a spring bar 90 and a spring retainer plate92. The spring bar 90 is secured to the damping end portion 16 of thehousing 12 using threaded fasteners received in axial threaded openingsin the dampening end portion 16 adjacent the check disc 82 (FIG. 3). Thespring rod 80 passes through openings in the spring bar 90 and thespring retainer plate 92. The spring retainer plate 92 is held on thethreaded end of the spring rod 80 with an adjusting nut 94. The springrod 80 is slidingly received by the check disc 82 and extends into thecylinder 17 where the end of the spring rod 80 is connected to the endof the piston 60 by means of a pin 98. The spring assembly 18 the urgesthe piston 60 towards the right end portion of the cylinder 17, as seenin the FIGs. An o-ring 86 surrounds the spring rod 80 for sealing thecylinder 17 against leakage of fluid. A channel-shaped spring cover 93secured to the dampening end portion 16 of the housing 12 surrounds thespring assembly 18. A spring block 95 is secured to the distal end ofthe spring cover. The adjusting nut 94 is accessible by tool from thebottom end of the housing 12 when a small cover 96 (FIG. 2) is removed.Rotating the adjusting nut 94 sets the initial compressed length of thesprings 88. A fluid medium, such as hydraulic oil, is provided in thecavity 15 in the housing 12 to cooperate with the piston 60, and thedampening end portion 16 of the housing 12 is provided with passagesthough which fluid is transferred from one side of the piston 60 to theother during reciprocal movement of the piston 60 in the cylinder forregulating movement of the door. Referring to FIGS. 3 and 5, a mainfluid passage 100 runs longitudinally from the distal end of the dampingportion 16 to an opening 102 into the cavity in the mechanical endportion 14 of the housing 12 and thus serves as a conduit for fluid topass between the damping portion 16 and the mechanical end portion 14 ofthe housing 12. Six longitudinally spaced radial passages 104, 106, 108,110, 112, 114 extend from ports that open into the cylinder and to themain fluid passage 100.

Three throttle devices 116, 118, 120 comprising needle valves inthreaded bores are longitudinally arranged along the main fluid passage100. The threaded bores are in fluid communication with the main fluidpassage 100. As seen in FIG. 2, a portion of the throttle devices 116,118, 120, including a regulating screw, are exposed through the bottomcover 11 of the housing 12. A tool can be applied to the screw to adjustthe axial position of the needle valve in the respective bore forselectively establishing the degree of constriction of the flow pathpast the needle valve for regulating the flow of fluid. This arrangementallows the movement speed of the door to be controlled based on theaxial positioning of the needle valves, particularly at the extremes ofthe closed position and fully open positions of the door. In particular,a back check valve 116 controls resistance near the fully opened doorposition, a stroke valve 118 controls the speed of the door in movingfrom an open position to near the closed position, and a latch valve 120controls the movement of the door as the door reaches the closedposition. For convenience, the valves 116, 118, 120 are identified withthe letters “BC”, “S” and “L” on the bottom cover 11 of the housing 12.

In keeping with the present invention, the door closer 10 is mounted inthe door frame above the door, preferably in a concealed position in theheader, or overhead portion of the frame. The end portion of the spindle20 is noncircular and extends from the housing 12 for being received ina complementary recess in the upper end of the door so that the door andspindle 20 turn together. The door is supported in the door frame forpivoting about the axis of rotation of the spindle 20 for movementbetween the closed position and an open position. In this arrangement,movement of the door causes the spindle 20 to turn in one direction andsubsequent moving from an open position to the closed position causesthe spindle 20 to turn in the opposite direction.

In operation, the components of the door closer 10 according to thepresent invention are as shown in FIGS. 1 and 3 when the door is in thefully closed position. As the door is opened, the door rotates thespindle 20. The cam 36 is rotated between the draw bar plates 42 withthe spindle 20. It is understood that the door closer 10 can be used ona left hand door or a right hand door and, therefore, the door could beopened in a either a clockwise or a counterclockwise direction, asviewed in FIGS. 1 and 3. Depending on which direction the door opens,one or the other of the opposed camming surfaces on the cam 36 bearsagainst the adjacent follower roller 50 which causes the slide assembly24 to move linearly to the left as seen in FIGS. 1 and 3. Because thedraw bar rod 44 is connected to the piston 60, the piston is also movedtoward the left end of the cylinder 17. Movement of the piston 60, inturn, carries the spring rod 80 to the left, thereby compressing thesprings 88 between the spring bar 90 and the spring retaining plate 92.

As the piston 60 moves toward the left end of the cylinder 17, the fluidinside the left end of the cylinder flows primarily through the twolarge diameter radial passages 106, 108 between the back check valve 116and the stroke valve 118 and into the main fluid passage 100. The fluidpasses through the opening 102 into the cavity 15 in the mechanical endportion 14 of the housing 12. Some of the fluid will also flow throughthe rightmost radial passage 108, into the piston 60 between thepressure relief valves 64, and out the end of the piston 60 through theball check valve 68 thus filling the right end of the cylinder 17. Asdescribed above, if the pressure in the fluid flow path becomesexcessive, the pressure may force the ball in the valve 66 in theleading end of the piston 60 to retract into the larger diameter portionof the passage so as to open the passage allowing fluid flow through thepiston 60 with relatively little hydraulic resistance.

As the door continues to open and the piston 60 moves further to theleft in the cylinder 17, the piston 60 gradually closes off the twopassages 106, 108. This occurs at a certain opening angle of the door,for example, at about 70 degrees. Fluid can now flow out of the cylinder17 only from the leftmost passage 104. Fluid entering this passage 104is directed through a passage 122 to the back check valve 116 and out tothe main fluid passage 100. As described above, the back check valve 116regulates the flow of fluid leaving the cylinder 17. Therefore,resistance to door opening begins as the fluid becomes a damper tohinder the movement of the piston 60 which slows down rotation of thespindle 60 and the door. When the door reaches a fully open position,the piston 60 is adjacent the left end of the cylinder 17 and thesprings 88 are compressed.

It is understood that the cam 36 is easily adapted for either 90-degreeor 105-degree door swing. The cam 36 may be provided with opposed radiusnotches (not shown) which can be entered by a roller 50 when the doorreaches an open position. The roller 50 drops into the notch where theresistance is enough to overcome the closing force of the springassembly 18 for maintaining the door in an open position. If the door isheld open, the door is easily closed by swinging it manually to clearthe roller 50 out of the notch whereupon the energy stored in thesprings 88 during opening of the door is released to move the door tothe closed position.

Movement of the door from an open position to the closed position iseffected by expansion of the spring assembly 18 acting to move thepiston 60 and the slide assembly 24 to the right as seen in FIGS. 1 and3. The engaged roller 50 bears against the camming surface of the cam 36causing the cam 36 and the spindle 20 to rotate for moving the doortoward the closed position. The cam follower 43 bears against thecamming surface on the opposite side of the cam 36 for controlling themovement of the door in the closing direction.

During the first portion of the closing movement of the door, the piston60 forces the fluid in the right end of the cylinder 17 through the twopassages 110, 112 between the stroke check valve 118 and the latch checkvalve 120. The speed of movement of the closing door will be regulatedby the flow of fluid past the stroke valve 118. As the door continues tomove toward the closed position, the leading end of the piston closesoff these fluid passages 110, 112. Typically this occurs as the doornearly reaches the closed position, for example, from about 5 degrees toabout 7 degrees from the closed position. The only available passage forfluid to exit the cylinder 17 is the passage 114 at the same axiallocation as the latch check valve 120 (FIG. 5). The speed of the doorthus slows and resistance to door closing builds as the fluid becomes adamper to hinder the movement of the piston 60. Fluid entering thisrightmost passage 114 is directed through a passage 124 and to the latchcheck valve 120. The latch check valve 120 operates to regulate the flowof fluid exiting the cylinder 17.

The back check disc 54 also cooperates during door closing to permitfluid in the mechanical end portion 14 of the housing 12 to flow intothe cylinder between the piston 60 and the back check disc 54. Thisoccurs because the fluid pressure is on the opposite side of the piston60 thereby freeing the balls from the passages in the ball check valves56 in the back check disc 54 allowing fluid to pass. It is understoodthat during door opening the flow of fluid from the cylinder to thecavity in the mechanical end portion 14 is prevented by the one-waycheck valves 56. Accordingly all of the fluid expelled from the cylindermust flow through the main fluid passage 100.

When the door reaches the closed position, the components of the doorcloser 10 are again as shown in FIGS. 1 and 3.

Although the present invention has been shown and described inconsiderable detail with respect to only a few exemplary embodimentsthereof, it should be understood by those skilled in the art that we donot intend to limit the invention to the embodiments since variousmodifications, omissions and additions may be made to the disclosedembodiments without materially departing from the novel teachings andadvantages of the invention, particularly in light of the foregoingteachings. For example, some of the novel features of the presentinvention could be used with any type of automatic door closer.Accordingly, we intend to cover all such modifications, omission,additions and equivalents as may be included within the spirit and scopeof the invention as defined by the following claims. In the claims,means-plus-function clauses are intended to cover the structuresdescribed herein as performing the recited function and not onlystructural equivalents but also equivalent structures. Thus, although anail and a screw may not be structural equivalents in that a nailemploys a cylindrical surface to secure wooden parts together, whereas ascrew employs a helical surface, in the environment of fastening woodenparts, a nail and a crew may be equivalent structures.

1. A door closer for automatically moving a door in a closing direction,the door positioned within a door frame and hinged along one edge to thedoor frame for movement between a closed position and an open position,the door closer comprising: a housing having a first closed end and anopen second end and defining an interior cavity including a cylindricalrecess spaced from the first end of the housing; a spindle journaled inthe housing adjacent the first end of the housing for rotation about anaxis, at least a portion of the spindle extending from the housing andadapted to be connected to turn with the door; a cam carried by thespindle for rotation with the spindle about the axis through an arc in afirst direction from a first angular orientation corresponding to theclosed position of the door to a second angular orientationcorresponding to an open position of the door and about the axis throughan arc in an opposite direction from the second angular orientation tothe first angular orientation, wherein rotation of the cam from thefirst angular orientation to the second angular orientation correspondsto movement of the door in the opening direction and rotation of the camfrom the second angular orientation to the first angular orientationcorresponds to movement of the door in the closing direction; a slideassembly including a cam following roller for cooperating with the camfor converting rotation of the cam into linear movement of the slideassembly relative to the housing; a piston having a first end and asecond end, the piston slidably disposed in the cylindrical recess; apiston rod connected at one end to the first end of the piston and atthe other end to the slide assembly; spring means disposed outside ofthe housing for urging the piston, the slide assembly and the cam in thedoor closing direction, the spring means including a spring rodconnected at one end to the second end of the piston; first and secondannular plugs disposed in the housing adjacent the ends of thecylindrical recess for slidably sealingly receiving the piston rod andthe spring rod, respectively, the first and second annular plugs andpiston dividing the cylindrical recess into a first chamber between thefirst annular plug and the first end of the piston and a second chamberbetween the second annular plug and the second end of the piston;passage means defined in the housing for permitting flow of fluidbetween the cylindrical recess and the space of the cavity definedbetween the first annular plug and the closed end of the housing inresponse to reciprocation of the piston in the cylindrical recess,wherein upon rotation of the spindle and cam in the door openingdirection the cam operates against the cam following roller for movingthe slide assembly toward the first end of the housing and the pistontoward the first end of the cylindrical recess and compressing thespring means for storing energy, the spring means urging the pistontoward the second end of the cylindrical recess for moving the slideassembly toward the second end of the housing and the cam followingroller against the cam to rotate the cam and the spindle in the doorclosing direction.